The late Stephen Jay Gould claimed that the panda’s thumb was suboptimal and, thus, counted as evidence for evolution over special creation. The claim may be considered not simply with regard to Gould’s particular contentions, but also as a way to examine broader philosophical and theological issues. In a recent peer-reviewed essay, and in posts at Evolution News (here, here, and here) and an ID the Future podcast (here), I have examined Gould’s iconic argument, using it as a platform for deeper discussion.¹

There are, as we’ll see, further reasons to reject the panda argument. These reasons apply far beyond the panda argument and far beyond Gould himself. If my analysis of the subject is correct, then many evolutionists ought to reject a whole range of suboptimality arguments — as well as a swath of other arguments for evolution. Ironically, the panda argument may do more harm than good for evolutionists. 

Gould and NOMA

Gould’s argument hinges upon theology: “God would not (likely) create or allow a suboptimal panda’s thumb.” Without this claim, the argument fails. It is a crucial feature of Gould’s case that the “clumsy” thumb counts as evidence in favor of evolution over divine design. He regards this as a scientific argument, which is why he repeatedly included it in his scientific writings for over twenty years, from 1978 to 2002.

But, of course, such an argument mixes science and theology. It uses a theology-laden premise in a scientific argument. Why might that be a problem? It is a problem because Gould himself claimed that such mixtures are verboten. He famously championed the doctrine of NOMA (non-overlapping magisteria). As he put it:

To summarize… the net, or magisterium, of science covers the empirical realm: what is the universe made of (fact) and why does it work this way (theory). The magisterium of religion extends over questions of ultimate meaning and moral value. These two magisteria do not overlap….. To cite the old clichés, science gets the age of rocks, and religion the rock of ages; science studies how the heavens go, religion how to go to heaven.²

As I note in my longer article:

But if science and religion “do not overlap”, then how can Gould’s argument about a biological phenomenon, like the panda’s thumb, rest upon theological claims? Indeed, in the panda argument, theological claims are essential. Remove these claims, and the argument’s conclusion no longer follows validly from the premises. More generally, all of Gould’s imperfection arguments — from zebra stripes to marsupial animals — turn upon God-talk. But if NOMA ought to be observed, then these arguments illicitly mix science and religion; as a result, they are illegitimate.³

Gould cannot have it both ways: either theology-laden arguments are legitimate within scientific discourse or not. If he wants to retain his panda argument, he must jettison NOMA. Or, if he wants to retain NOMA, he must jettison the panda argument. The choice is binary.

Deeper and Wider Problems

This same incoherence plagues others:

More generally, anyone who accepts an epistemic barrier between science and religion faces the same dilemma. Both compartmentalists and complementarians do so. The former assent to NOMA, while the latter believe that science and religion offer complementary perspectives on at least some of the same natural phenomena. Both generally hold that the content of a scientific theory cannot raise or lower a person’s epistemic justification for a religious claim. So, too, the content of a religious claim cannot raise or lower a person’s epistemic justification for a scientific theory. Yet in the panda argument, a theological claim purports to provide readers with increased justification for belief in evolutionary theory. Accordingly, compartmentalists and complementarians cannot coherently deploy the panda argument — or any of the many theology-laden arguments currently in play.⁴

In other words, thinkers face a dilemma if they say “science” and “theology” cannot impinge upon each other’s truth (or falsity). If they retain this view, then they must eschew scientific arguments that rely on theology-laden claims (such as the claim that “God wouldn’t create or allow a suboptimal panda’s thumb.”) On the other hand, if they retain the panda argument, then they must reject their particular model of the relationship between science and theology. They face a binary choice.

But the problem runs deeper. It turns out that quite a number of scientists use theology-laden arguments in their scientific case for evolution:

[L]ike Gould, a number of prominent biologists do offer theology-laden arguments for evolution, sometimes as their self-reported best stand-alone argument for the theory. These luminaries include Theodosius Dobzhansky, Niles Eldredge, Douglas Futuyma, Francisco Ayala, Jerry Coyne, Émile Zuckerkandl, Richard Dawkins, George Williams, Francis Collins, Kenneth Miller, and others. Their theology-laden arguments surface in major areas: molecular homology, embryology, biogeography, paleontology, gross anatomy, dysteleology, organic diversity, and the like.⁵

Advocates of NOMA or any similar view should set all such arguments aside. Whatever their defense of evolution is, it must come from elsewhere. 

Theology-laden arguments are also found in many biology and evolution textbooks:

Some prominent biologists likewise use positive theology in some of their arguments for evolution. This occurs not just in debates with creationists or intelligent design theorists but even in “neutral” or “purely scientific” contexts like encyclopedia entries or textbooks (Nelson 1996, pp. 497, 506-8). That is, even when the rhetorical setting is a straightforward description of the reasons for evolution, theological claims often surface. In fact, a 2019 study of 32 biology (and evolution) textbooks — including the top 12 in the United States — indicated that around 80% of them use theology in a tendentious way in their case for evolution (Dilley and Tafacory 2019). Thus, some of the challenges that plague the panda argument apply elsewhere too.⁶

According to NOMA and similar views, all theology-laden arguments are disallowed within a scientific context. What then to make of all these textbooks and their pro-evolution arguments? 

It seems that, when rhetorically convenient, thinkers like Gould and these textbook authors will claim that “science” and “theology” do not impinge upon each other. But in other contexts, they are perfectly willing to invoke their preferred claims about God in order to support their favored scientific theory. The underlying constant in this muddle is a commitment to say whatever is expedient to promote an evolutionary perspective.

Methodological Naturalism?

A similar dynamic infects those who accept methodological naturalism (MN), which prohibits God-talk in science. If one accepts MN, then one cannot coherently say that the panda argument is a good scientific argument. More generally, under MN, a person cannot allow into science any argument that relies on theology (“God would not create X”). So, methodological naturalists should reject as “unscientific” all theology-laden arguments for evolution in textbooks and in the works of luminaries from Darwin to Dobzhansky.⁷

Yet many who accept theology-laden arguments for evolution also endorse MN. Theistic evolutionists, for example, routinely fall into this trap.⁸

Doubled-Edged Sword

In the end, the panda argument cuts both ways. Even if the argument were sound — and I have shown that it is not — it would pose an acute problem for evolutionists who accept NOMA, complementarity, or methodological naturalism. It turns out that, depending on one’s other commitments, the panda argument might not be such a good argument for evolution at all.

And a similar dynamic holds for a range of arguments — from top biologists and top textbooks — that likewise rely on God-talk. If such arguments are no longer scientifically legitimate, then surely the case for evolution is not nearly as robust as Gould and others have wished to think.

Notes

1. Dilley, Stephen. 2023. “God, Gould, and the Panda’s Thumb.” Religions 14: 1006. https://doi.org/ 10.3390/rel14081006.
2. Gould, Stephen Jay. 1999. Rocks of Ages. New York: Ballantine Books, p. 6.
3. Dilley, “God, Gould, and the Panda’s Thumb,” p. 21.
4. Dilley, “God, Gould, and the Panda’s Thumb,” p. 21.
5. Dilley, “God, Gould, and the Panda’s Thumb,” p. 2.
6. Dilley, “God, Gould, and the Panda’s Thumb,” p. 20. The citations in the quote refer to: Nelson, Paul. 1996. “The Role of Theology in Current Evolutionary Reasoning.” Biology and Philosophy 11: 493-517. Dilley, Stephen, and Nicholas Tafacory. 2019. “Damned if You Do and Damned if You Don’t.” Communications of the Blythe Institute 1: 37-70.
7. Dilley, Stephen. 2017. “How to Lose a Battleship: Why Methodological Naturalism Sinks Theistic Evolution.” In Theistic Evolution. Edited by J. P. Moreland, Stephen Meyer, Christopher Shaw, Ann Gauger and Wayne Grudem. Wheaton: Crossway, pp. 593–631.
8. Ibid.